Jet-actuated membrane pump

ABSTRACT

The invention relates to a pump having a reservoir having an inlet thereto and an outlet therefrom, and a membrane defining at least part of one wall of the reservoir and movable alternately to draw fluid into the reservoir through the inlet and to expel fluid from the reservoir through the outlet, a membrane serving to open and close the inlet and a membrane serving to open and close the outlet. One or more membranes may be used and the or each membrane is preferably movable in response to changes in fluid pressure on the opposite side thereof to the reservoir.

United States Patent [191 Nystroem June 26, 1973 1 1 JET-ACTUATEDMEMBRANE PUMP [22] Filed: Apr. 5, 1971 [21] Appl. No.: 131,055

[30] Foreign Application Priority Data 2,529,028 11/1950 Landon 417/395X 2,980,032 4/1961 Schneider 417/395 X 3,307,481 3/1967 De Castelet417/395 X 3,533,387 10/1970 Kaneko 417/395 X 862,867 8/1907 Eggleston417/395 X Primary ExaminerWilliam L. Freeh Assistant Examiner-John T.Winburn Att0rney-Beveridge & DeGrandi 571 1 ABSTRACT The inventionrelates to a pump having a reservoir having an inlet thereto and anoutlet therefrom, and a membrane defining at least part of one wall ofthe reservoir and movable alternately to draw fluid into the reservoirthrough the inlet and to expel fluid from the reservoir through theoutlet, a membrane serving to open and close the inlet and a membraneserving to open and close the outlet. One or more membranes may be usedand the or each membrane is preferably movable in response to changes influid pressure on the opposite side thereof to the reservoir.

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ERNST NOLGER at RT! L N YS ROEH PATENTEDJUNZB I975 SHEEI Q 0F 4INVENTOR:

' ERNST "mom Bewrn. NYSTROEH JET-ACTUATED MEMBRANE PUMP The presentinvention relates to a pump.

According to the present invention a pump comprises a reservoir havingan inlet thereto and an outlet therefrom, a membrane defining at leastpart of one wall of the reservoir and movable alternately to draw fluidinto the reservoir through the inlet and to expel fluid from thereservoir through the outlet, a membrane movable to open and close theinlet and a membrane serving to open and close the outlet.

One or more membranes may be used to define at least part of one wall ofthe reservoir and to open and close the inlet and the outlet.

The membrane is preferably movable in response to changes in fluidpressure on the opposite side thereof to the reservoir. The fluidpressure may be for example oil pressure, air pressure water pressureetc.

In one preferred embodiment of the invention the pressure applied to themembrane is created by one or more (preferably two) jet pumps.

In applications where the fluid being pumped is to be added to a flow ofanother fluid, that other fluid may be the jet medium in the jet pump.

' The changes in pressure are preferably achieved by alternately raisingand lowering the pressure on the opposite side of the membrane to thereservoir in areas opposite the reservoir, the inlet and the outlet.

The pressure required on the opposite side of the membrane duringpressurisation-and depressurisation depends upon the use towhich thepump is being put. If the inlet of the pump receives a liquid ofacertain pressure then the depressurisation-pressure must be below thatpressure of the liquid. For instance if water is to be pumped and thewater level is at atmospheric pressure and placed 2 metres below theinlet to the pump then depressurisation-pressure must be less than 0.8of the atmospheric pressure in theory and in practice still somewhatless. This is to overcome the suction to the pump. On the other hand ifthe liquid at the inlet has a pressure of 2 kg/cm then thedepressurisationpressure can be more than the atmospheric pressure andup close to but less than 2 kglcm In addition thepressurisation-pressure must be higher than the pressure of the liquidat the outlet of the pump.

The selective pressurisation and depressurisation of the compartmentscan be controlled by various methods e.g. by the use of valves (usuallysolenoid valves) and timers or in an especially preferred embodiment byusing the well known techniques of fluid logics (or fluidics). Thepresent invention thus envisages a valve of the types described, inwhich the compartments are pressurised and depressurised usingfluidistor technol- In one arrangement the reservoir is formed as ahollowed out portion in a solid memben'Two further'hollowed out portionsor cavities are also formed in the solid member (in the same face as thereservoir or in an opposite face) and are connected to the reservoir bypassages. The further hollowed out portions also have additionalpassageways leading thereto for connection to a source of fluid and to adelivery point. Fluid is caused to flow by alternately and sequentiallyraising and lowering the pressure inareas on the opposite side of themembrane to the three hollowed out portions or cavities.

By arranging a smooth or streamlined path for the fluid being pumpedthrough the pump a low turbulence pump may be obtained. Such a pump isof great value in pumping blood through a human body. Other uses of thepump of the present invention include laboratory pumps and pumps forsupplying chemicals for example the addition of chemicals to swimmingpools and the addition of fertilizer in water for watering plants.

The invention will now be further described by way of example withreference to the accompanying drawings, in which:

FIG. 1 of which is an exploded view of a pump embodying one form of thepresent invention,

FIG. 2 is a plan view of a part of a pump embodying an alternative formof the invention,

FIG. 3 is an exploded view of a pump embodying another form of thepresent invention,

FIG. 4 is an exploded view of a pump embodying a further form of theinvention, and

FIG. 5 is a cross-sectional view of a pump embodying yet a further formof the invention.

Referring now to FIG. 1 the pump shown comprises two solid members 10and 12 between which is located a membrane 14. For clarity member 10 isrotated slightly with respect to member 12 and membrane 14 in order toclearly show front face 15. The member 10 includes a reservoir 16 whichis formed as a cavity in the face 15 of the member 10. An inletpassageway 18 extends between the front and back faces of the member 10and is surrounded by an annular channel 20 formed in the front face 15of the member 10. A similar arrangement comprising an outlet passage 22and an annular channel 24 is also provided in the member 10. A series ofpassageways 26 connects each of the annular channels 20, 24 with thereservoir 16. The member 12 is formed with a cavity 28 which will lieopposite the reservoir 16 when the pump is assembled. A blind passageway30 extends into the member 12 and a pair of jet pumps 32, 34 areconnected to the blind passageway 30. The area downstream of therestrictions in the jet pumps 32, 34 arev connected to cavities 33, 35respectively formed in the front face of member 12. The cavity 33 is incommunication with the cavity 28 via a very narrow bore passageway 37. Aslot 29 is formed in the wall of the cavity 28 and the passageway 37 isconnected to this slot 29. A three-way valve arrangement 36 (showndiagrammatically) selectively connects either jet pump 32 or jet pump 34with an outlet pump 38. The three-way valve is operated by a timer 40(shown diagrammatically).

In the arrangement shown the members 10 and 12 and the membrane 14 areheld together e.g. by nuts and bolts 42.

In operation jet pump 32 is first connected to outlet pipe 38 and a jetmedium is flowed through passageway 30 and jet pump 32 to outlet 38. Anarea of low pressure is thereby created within the chamber 33. Thisdraws membrane 14 away from inlet passage 18 thereby opening the inletand at the same time creating an area of low pressure around the inlet.The low pressure draws the fluid to be pumped through the inlet 18 froma supply (not shown) and into the annular channel 20. The passageway 37which connects chamber 33 with chamber 28 is of extremely smallcross-section and creates a low pressure area within chamber 28 shortlyafter the creation of the low pressure area in the chamber 33. The lowpressure in chamber 28 draws membrane 14 into chamber 28 therebyexpanding reservoir 16 and drawing fluid from channel 20 throughpassageway 26 into the reservoir 16. During this period build up offluid in passage 30 to the right of jet pump 33 as viewed creates anarea of high pressure in chamber 35 which acts on the membrane 14 tokeep outlet passage 22 closed. The three-way valve under operation ofthe timer 40 then connects jet pump 34 to outlet pipe 38 andsimultaneously disconnects jet pump 32 from outlet pipe 38. This createsan area of low pressure in chamber 35 which draws the membrane intochamber 35 at that point. The annular channel 24 is thus subjected to areduction in pressure thereby causing fluid to be drawn throughpassageway 26 from reservoir 16 into annular channel 24. Build up offluid within passageway 30 now creates an area of high pressure inchamber 33 which by action of the membrane 14 closes inlet passageway18. By virtue of the connection between chambers 28 and 33, an area ofhigh pressure is created within chamber 28 shortly following thecreation of the area of high pressure in chamber 33. This area of highpressure in chamber 28 forces membrane 14 into reservoir 16 expellingfluid from reservoir 16 through passageway 26 into annular channel 24and subsequently through outlet passageway 22. Under control of thetimer the three-way valve continuously alternates the connection ofoutlet pipe 38 between jet pumps 32 and 34 in a pulsating manner andthereby creates a pumping effect through the reservoir 16.

The members and 12 may be replaced by an arrangement in which flow fromthe inlet 18 to the outlet 22 through the reservoir is streamlined flowor at least flow of very low turbulence. Such an arrangement is shown inFIG. 2. In this arrangement the path between inlet 18 through reservoir16 to outlet 22 is smoothed out by the shape of the cavity formed inmember 10. Clearly with this arrangement the arrangement of block 12will have to be adjusted accordingly.

Referring now to FIG. 3, the pump shown comprises two solid members 50,52 between which is located a membrane 54. The member 50 includes areservoir 56 formed as a cavity in face 58 of the member 50. Two smallercavities 60, 62 are also formed in the face 58 of the member 50. A slot64 is formed in the wall of the reservoir 56 and passages 66, 68 connectthe slot 64 with cavities 60 and 62 respectively. Cavities 60 and 62 areprovided with further passageways 70, 72 respectively connecting thesecavities to the side faces of the member 50.

The member 52 is provided with three cavities 74, 76, 78 which areexactly opposite cavities 56, 60 and 62 respectively when the pump isassembled. The cavities 74, 76, 78 are connected with valves 80, 82, 84respectively by passages 86, 88, 90. The valves 80, 82, 84 canselectively connect passageways 86, 88, 90 with a source of eithervacuum or pressure via conduits 92. Each of the valves 80, 82, 84 iscontrolled by means of a timer 94. The two solid members and themembrane may be held together by nuts and bolts 96.

In operation the valves are co-ordinated so that at any one time cavity74 is in the same condition (i.e. connected with a source of pressure orvacuum) as one of the other cavities 76 and 78. The operation will bedescribed by reference to the case where cavity 74 is in the samecondition as cavity 78. Starting from the condition in which valves 80and 84 connect passageways 86 and 90, and thus the cavities 74 and 78,with a source of pressure so that the passage 72 is closed and thevolume of the reservoir 56 is minimised, and in which valve 82 connectspassageway 88 and thus cavity 76 with vacuum so that passageway 70 isopen, the sequence of operation is as follows:

Under the influence of the timer 94 the positions of the three valvesare reversed thereby connecting the passages 86 and 90 with a source ofvacuum and the passage 88 with a source of pressure. The passageway 70is thereby closed, the passageway 72 opened and the volume of thereservoir 56 increased. During this part of the operation fluid is drawnin through passageway 72 and passes through cavity 62 and passageway 68to the reservoir 56. The timers again reverse the position of the threevalves and thereby closing the passageway 72, and opening the passageway70. The volume of reservoir 56 is decreased and fluid present in thereservoir 56 is passed via passageway 66 and cavity 60 to the passageway70. In order to achieve a very smooth pumping action or if the reservoir56 is small then the action of valve 80 may be slightly delayed withrespect to valve 84.

The pump shown in FIG. 4 is the same as that of FIG. 3 with theexception that the cavities 56, 60, 62 are omitted and the passageways66, 68, 70, 72 extend to the surface 58 of the member 50. In thisarrangement the reservoir thus comprises the passageways 66 and 68(which are joined together and include a common portion 67) and thevolume between the membrane 54 and the surface 58 created when themembrane is drawn into cavity 74. In this arrangement the capacity ofthe pump may be brought up to that of the pump of FIG. 3 or altered inany other way by altering the volume of the cavity 74. The advantage ofthis arrangement is that the member may be reduced in size. The member50 is one of the components which comes into contact with the fluidbeing pumped and which must be made from a material which is inert tothe fluid being pumped. Such materials may well be expensive (e.g. ifTeflon is used) and the reduction in size of member 50 thus enableseconomies in cost. The other component which comes into contact with thefluid being pumped is the membrane. This may conveniently be made fromViton.

The arrangement shown in FIG. 5 is similar to that shown in FIG. 3 withthe exception that cavities 60, 62 are formed in the opposite face ofmember 50 to the reservoir 56 and cavities 76, 78 are formed in a thirdmember 98 separated from member 50 by a second membrane 100. Operationof the pump of FIG. 5 is the same as described in connection with FIG.3.

If desired either cavities 76, 78 or cavities 60, 62 may be omitted.

This arrangement ie. that of FIG. 5 may provide smoother flow than thearrangements of FIGS. 1, 3 and 4.

In the arrangements of FIGS. 3, 4 or 5 where the pump is being used forclosing swimming pools, the suction from the circulating pump normallyused in the pool may be utilised to provide the source of vacuum for thevalves 80, 82, 84 and the outlet pressure from the circulating pump maybe used as the source of pressure for the valves 80, 82, 84.

The timers mentioned above may be either electronically or mechanicallyoperated. Electronically controlled timers include for instance thetriac and thyristor equipped timers and their frequency in switching isvaried by one or more potentiometers. Mechanically operated switchesinclude for instance motor-operated switches and the frequency can bevaried by varying the speed of the motor.

It will be appreciated that many modifications of the arrangements shownin the drawings may be effected. For example in the arrangement shown inFIG. 3 the valve 80 may be omitted and the passageway 86 connected witheither the passageway 88 or the passageway 90 depending upon the desireddirection of pumping. By arranging the connection between the passageway86 and either the passageways 88 or 90 to be much smaller thanpassageway 86 or 84 a similar effect to delaying the action of valve 80may be achieved. A delaying effect could also be achieved by locating avalve in the connection between passageway 86 and either the passageway88 or the passageway 90, which valve is arranged to open only in onedirection and only when a predetermined pressure has been reached. Thispredetermined pressure can be chosen such that the inlet to the pump isalways either opened or closed before the predetermined pressure isreached at this valve.

A further possible modification of the arrangements of FlGS. 1 to 3involves the omission of the three cavities in one or other of themember and 12 or in member 52. In this event the capacity of the pumpwill be reduced unless the cavity 56, 16 or 28 on the other side iscorrespondingly increased in volume.

In a further modification the members 10 and 12 or 50 and 52 may beother than flat e.g. they may be curved, spherical or angled.

If desired the membrane need extend only just beyond the area of thecavities and need not cover the whole area between the members 50, 52 or50, 54.

In all the arrangements described in the drawings the pressurisation anddepressurisation is controlled by valves (usually solenoid valves)operated by timers. The timer and/or the valve may if desired bereplaced by an arrangement employing fluidics (fluid logics) techniquesi.e. employing fluidistor technology.

The capacity of the pump of the invention depends inter alia upon howoften the timers switch per period of time. Each time the pump reservoirdecreases in volume the pump liquid is pressed out from the pump andeach time the pump reservoir increases in volume this is interrupted. Inmany cases this pulsing action of the pumping is of no importance. Toachieve a smoother pumping action it is possible to equip the pump wthtwo or more co-operating pump reservoirs each one with its own inlet andoutlet membrane valve.

I claim:

1. A pump comprising a reservoir, an inlet to said reservoir and anoutlet from said reservoir, a pumping membrane defining at least part ofone wall of the reservoir and movable alternately to draw fluid into thereservoir through the inlet and to expel fluid from the reservoirthrough the outlet, means including a first jet pump for moving thepumping membrane by alternately subjecting the face thereof which liesopposite the reservoir to fluid pressure and vacuum, a first valvingmembane movable to open and close the inlet, a second valving membranemovable to open and close the outlet, said first jet pump being operableon the first valving membrane to move it between its opening and closingpositions by alternately subjecting one face thereof to fluid pressureand vacuum, and means including a second jet pump for alternatelysubjecting one face of the second valving membrane to fluid pressure andvacuum to move the second valving membrane to its opening position whenthe first valving membrane is in its closing position and to move thesecond valving membrane to its closing position when the first valvingmembrane is in its opening position.

2. A pump according to claim 1, wherein a single membrane defines atleast part of one wall of the reservoir, serves to open and close theinlet and serves to open and close the outlet.

3. A pump according to claim 1, wherein each membrane is movable inresponse to changes in fluid pressure on the opposite side thereof tothe reservoir.

4. The pump of claim 1 having valve means for intermittently obstructingthe flow of fluid leaving each of the jet pumps, whereby the jet pumpcreates a vacuum on the face of its respective membrane when the valvemeans is open and the jet pump exerts a pressure on the face of itsrespective membrane when the valve means is closed.

5. A pump according to claim 1, wherein the reservoir is formed as ahollowed out portion in a solid memher, at least two further hollowedout portions also being formed in the solid member, said furtherhollowed out portion being connected to the reservoir and to exteriorwalls of the solid member by passageways, a membrane extending acrossthe reservoir and each of the at least two further hollowed outportions.

6. A pump according to cliam 5 wherein the hollowed out portions,corresponding to the reservoir and the at least two further hollowed outportions, are formed in at least one further solid member located on theopposite side of a membrane to the reservoir and the at least twofurther hollowed out portions in the first solid member.

7. A pump according to claim 5, wherein the reservoir is formed in anopposite face of the solid member to said at least two further hollowedout portions, and a first membrane defines at least part of one wall ofthe reservoir and a second membrane serves to open and close the inletand the outlet.

8. A pump according to claim 6, wherein the reservoir is formed in anopposite face of the solid member to said at least two further hollowedout portions, and a first membrane defines at least part of one wall ofthe reservoir and a second membrane serves to open and close the inletand the outlet.

I F l

1. A pump comprising a reservoir, an inlet to said reservoir and anoutlet from said reservoir, a pumping membrane defining at least part ofone wall of the reservoir and movable alternately to draw fluid into thereservoir through the inlet and to expel fluid from the reservoirthrough the outlet, means including a first jet pump for moving thepumping membrane by alternately subjecting the face thereof which liesopposite the reservoir to fluid pressure and vacuum, a first valvingmembane movable to open and close the inlet, a second valving membranemovable to open and close the outlet, said first jet pump being operableon the first valving membrane to move it between its opening and closingpositions by alternately subjecting one face thereof to fluid pressureand vacuum, and means including a second jet pump for alternatelysubjecting one face of the second valving membrane to fluid pressure andvacuum to move the second valving membrane to its opening position whenthe first valving membrane is in its closing position and to move thesecond valving membrane to its closing position when the first valvingmembrane is in its opening position.
 2. A pump according to claim 1,wherein a single membrane defines at least part of one wall of thereservoir, serves to open and close the inlet and serves to open andclose the outlet.
 3. A pump according to claim 1, wherein each membraneis movable in response to changes in fluid pressure on the opposite sidethereof to the reservoir.
 4. The pump of claim 1 having valve means forintermittently obstructing the flow of fluid leaving each of the jetpumps, whereby the jet pump creates a vacuum on the face of itsrespective membrane when the valve means is open and the jet pump exertsa pressure on the face of its respective membrane when the valve meansis closed.
 5. A pump according to claim 1, wherein the reservoir isformed as a hollowed out portion in a solid member, at least two furtherhollowed out portions also being formed in the solid member, saidfurther hollowed out portion being connected to the reservoir and toexterior walls of the solid member by passageways, a membrane extendingacross the reservoir and each of the at least two further hollowed outportions.
 6. A pump according to cliam 5 wherein the hollowed outportions, corresponding to the reservoir and the at least two furtherhollowed out portions, are formed in at least one further solid memberlocated on the opposite side of a membrane to the reservoir and the atleast two further hollowed out portions in the first solid member.
 7. Apump according to claim 5, wherein the reservoir is formed in anopposite face of the solid member to said at least two further hollowedout portions, and a first membrane defines at least part of one wall ofthe reservoir and a second membrane serves to open and close the inletand the outlet.
 8. A pump according to claim 6, wherein the reservoir isformed in an opposite face of the solid member to said at least twofurther hollowed out portions, and a first membrane defines at leastpart of one wall of the reservoir and a second membrane serves to openand close the inlet and the outlet.
 9. The pump of claim 1 having valvemeans for intermittently obstructing the flow of fluid leaving each ofthe jet pumps, whereby the jet pump creates a vacuum on the face of itsrespective membrane when the valve means is open and the jet pump exertsa pressure on the face of its respective membrane when the valve meansis closed.